Изображения страниц

From all observed times of the end, if expressly so given, twenty-six seconds has been deducted for the beginning, as above. Wherever no mention is made of the period in the shock to which the observation applies, the times stated in the notices respectively have been inserted in the table without change, as being the presumed time of the beginning.

An inspection of this table discloses no considerable northand-south movement. A nearly east-and-west progress is that which appears most consistent with the aggregate of times. Indeed it presents itself as the only one at all consistent with a uniform and regular progress. Nor is there discovered in the table any decisive indication of a change of direction as between the east and the west of the Alleghanies; but the various accounts, so far as they go, indicate the very reverse. Thus the direction of N.E and S. W., noted at Brunswick, was accurately N. 10° E. at Harvard Observatory, while it was N.N.E. at New Haven, and almost identically the latter also at Chicago. But at Cleveland and Detroit it is described as E. and W., and at Burlington, Vt., N. and S. One account from Boston makes it, incorrectly, N.W. and S.E., and another from Hartford the same at the latter place.

The best approximate result appears to be that the earthquake made progress from about E. 6° N. to about W. 6° S., at the rate of one hundred and sixty miles a minute, being six minutes and a half from St. Johns to Chicago; while surprisingly, the ordinary direction of the subordinate undulation was about N. by E. But there was not absolute regularity of rate in any single direction. The times at Cambridge, at Albany and at New Haven compared together, disclose appreciable deviations from the general regimen of the table ; and the same is probably true with respect to the Cleveland observation. Unfortunately the latter was not checked by comparison with a standard time-piece,-neither, as is probable, was the Owen's Sound observation. That at Cincinnati does not purport to be more than a loose approximation.

It appears by observations of Prof. Hough at Dudley Observatory, obligingly furnished me by him, that the principal shock was observed at 116 15m, being a few seconds in duration, but that a tremor continued for at least a minute. No doubt there exist, at various localities not heard from, many observations recorded or distinctly remembered. It is desirable yet to have them communicated to this place, or to some one elsewhere, by whom they will be made available.

In fact while this article is in press, I am furnished through the favor of H. Paton, Esq., of the Montreal Telegraph Co. at Quebec, with the following important statements by Mr. Robert McCord, the operator who made inquiries immediately after


the cessation of the earthquake at that office, and received replies from Montreal. His condensed statements are: “All perceptible motion was over here by the time I had finished telegraphing to Montreal—do you feel earthquake. It would take about eight seconds to telegraph the words used. The operator's immediate reply was—no.

About fifteen seconds after, he said -here it is. The gentleman at Montreal afterward explained that, although he said no, he did experience a slight movement at the time, but was not aware that it was caused by an earthquake. He telegraphed—here it is—on the instant that the shock became sensibly evident. He cannot say how long the vibration lasted after that period, accurately, but is of opinion it continued for nine or ten seconds. The following further particulars be may of interest. The shock passed over this district from a northerly direction,-a rumbling sound accompanied the shock, resembling that produced by ponderous machinery, noise and motion increased steadily for some seconds, and gradually passed away. Buildings were violently shaken. Our office being in the upper part of a high brick building, the trembling was powerfully felt-the clock in the office was stopped by it at 11:25, but am not certain if the time by it previous to the shock was correct. Some observers say the shock was first felt here a few seconds before 11:24, and lasted forty seconds -others state fifty or sixty seconds. I am of opinion it lasted sixty seconds. No two opinions agree as to the commencement and duration."

"At Bay St. Paul and Les Eboulements-places about ninety or one hundred miles northeast of Quebec—the ground opened in several places, and water was thrown up. Slight elevations of land in some places were produced. The country in the vicinity of St. Paul's Bay is of volcanic formation, and slight shocks are of frequent occurrence. A gentleman from that vi. cinity informs me that they had twenty or thirty slight shocks within the past two weeks. The shock on the 20th, here, did not appear to have an undulating, upheaving motion, but to partake of a tremulous nature.”

"The operator at Richmond, a place ninety miles southwest of here, says the shock was just passing away there at the period when I made the inquiry of Montreal.”

Mr. McCord does not refer to specific authority for the convulsive effects at Baie St. Paul and Les Eboulements, some 55 to 62 miles in a direct line from Quebec; but they are in gene

а ral conformity to what has long been known to British geologists respecting the volcanic character of the region specified. They, in fact, recall and confirm the representations made at page 236, vol. xxx of this Journal, 1836, in a paper by Capt. R. H. Bonnycastle, R. En. In that region, very probably, lay the initial spot of the disturbance. The subject, in this view of it, merits a more extended investigation, and it is hoped that the statement here brought out will induce new communications relative to the facts.

The interpretation of Mr. McCord's interesting statements relative to the telegraphic communication, seems to be as follows: He occupied the last eight seconds of the motion at Quebec with a question put to Montreal

. That question, together with the answer “no," I find by careful trial at the American Telegraph office, require not less than eighteen seconds for transmission and reception. Then there are estimated fifteen seconds of interval. Then there was the second reply of not less than eight seconds; then there were nine or ten seconds to the end of the vibrations. In other words, there transpired not less than forty-two seconds between the end of the message and of the tremors at Quebec, and the end of the same at Montreal, ninety-six miles distant in longitude, and one hundred and fifty. nine in a line N. 51° E., and which in the table above had been and still remains credited with the empirical interval of thirty: nine seconds,-showing a near accordance between these and the other facts, and 137 miles per minute of east-and-west progress.

Again, the Montreal "no" was given just as the tremors there began, and after-say six seconds after the end of the shock at Quebec; that is to say, the beginning traversed from city to city in some six seconds more than the duration of the shock. Consequently the latter, in consistency with the above, must have continued about thirty-six seconds, in place of the twentysix seconds ascertained at New Haven. Still again, the shock at Montreal began with the “no," which may have occupied four seconds. Then there were fifteen seconds of interval ; then eight of reply; then nine to ten of estimated continuance; in all thirty-six or thirty-seven seconds for the duration of the shock. The principal movement at Montreal did not come till at least fifteen seconds after the beginning; and the testimony of the Richmond operator shows that the violence of the shock there had passed, while the tremors at Quebec were still in faint continuance. Finally, it will be observed that the time of occurrence stated by Mr. McCord and others—although not confirmed by his comparison with any standard time-piecetends to represent the actual occurrence at Quebec to have been before the empirical time of column 5 in the table, instead of 1" 16" later, as shown in column 7.

ART. XI.-Brief Contributions to Zoology from the Museum of

Yale College. No. X.- Descriptions of some imperfectly known and new Ascidians from New England; by A. E. VERRILL.


[ocr errors]

Molgula Manhattensis Verrill. Figure 1. Molgula Manhattensis Dekay, Report on the Natural History of New York,

Mollusca, p. 259, 1843; Binney, in Gould's Invertebrata of Massachusetts, 2nd ed., p. 25, 1870, (copied from Dekay).

BODY somewhat oval, subglobular, or slightly cordate, usually somewhat compressed laterally ; when crowded often slightly adhering together laterally and more or less deformed; usually adhering to eel-grass (Zostera) and various sea-weeds, or to the

under side of stones, by the left side, or obliquely by the basal portion. The surface including the tubes is generally thickly covered with fragments of eel-grass, broken shells, particles of sand, and various kinds of debris so as to entirely conceal the surface and disguise the form ; sometimes, however, in sandy regions the surface is nearly destitute of such covering. The integument is firm and thick, and when clean it is translucent

and roughened throughout with minute, granule-like papillæ, which are larger and more crowded on the upper part and around the base of the tubes, where they often form small, rough, unequal verrucæ. The tubes originate on the upper side, a little apart, the distance between usually about equal to the diameter of the anal tube ;* they are both rather long and diverge by curving outward from the base. The anal tube is smaller and somewhat longer than the branchial, usually about equal in length to half the diameter of the body, and tapers to the end, which is rounded and has a small square aperture, its sides, near the end and often below, are usually roughened by irregular, uneven papillæ. The branchial tube is shorter and stouter, widest at base, truncate at the end, with six, small

, obtuse, rounded papillæ surrounding the orifice; outside of these there are six, short, triangular lobes; below these there is often an irregular circle of about six to twelve rougher papillæ, alternately larger and smaller, and sometimes other more irregular ones below, between the sulcations; these are, however, sometimes wanting, as in the specimen figured. In contraction the tubes form low, rough verruca, the anal often four-lobed, both covered with rough, irregular papillæ.

The inner tunic, which is closely adherent to the outer, is smooth, pellucid, light greenish, the dark intestine and a reddish organ below it showing through.

* The figure represents them as arising nearer together than is usually the case. * The expeditions of 1859 and 1863 were by the author; that of 1864 by the author and S. I. Smith; that of 1868 by A. E. Verrill, S. I. Smith, H. E. Webster and Geo. A. Jackson; that of 1870 by A. E. Verrill


[ocr errors]


In life the body and tubes are pale yellowish green or olive; the branchial orifice is sometimes surrounded within by a ring of dull reddish brown, the six lobes have each a spot of dark brown, with smaller ones between. The anal orifice is greenish yellow.

Diameter of the largest specimens seen, about 1 inch.

New York Harbor, -Dekay; Fire I., Long Island, abundant on eel-grass, -S. I. Smith ; New Haven Harbor, on eel-grass, abundant-A. E. Verrill ; near New Haven Light on sea-weed, and at Savin Rock, under stones at low-water mark, -A. E. Verrill.

Molgula pannosa Verrill, sp. nov. Figure 2. Body subglobular, or a little elongated, somewhat compressed laterally, entirely covered, except the ends of the tubes, with a firm and thick covering, composed of fragments of shells, echini, zoophytes, wormtubes, foraminifera, grains of sand, pieces of sea-weed, and other debris. The surface of the integument, when the foreign matter is removed, is densely covered with small granule-like papillæ, which give rise to very abundant, long, fine fibrous processes, by which the foreign matters are entangled ; the basal portion of the tubes is covered with similar processes, though less numerous, which decrease toward the end, leaving the terminal portion nearly smooth. The tubes, which arise close together, are short, conical, a little divergent. The anal tube is a little longer than the branchial, swollen at base, tapering, and

rounded at the end, which has a very small square aperture. The branchial tube is about the same in size, but a little shorter, subcylindrical, scarcely tapering, with six, small, prominent, acute lobes or papillæ; alternating with these are six much smaller ones. In contraction the tubes can be wholly withdrawn, and then the body looks like a more or less irregular ball of dirt.

In life the color of the clean integument is a dull, dark, grayish green; the tubes lighter, or dull olive-green.

A large specimen, when expanded, was 1 inch in length; 75 broad; 50 thick.

Eastport, Me., 10 to 50 fathoms, muddy and shelly bottoms, -Expeditions of 1868 and 1870; off Head Harbor, Campo Bello I., 80 fathoms, muddy,-Expedition of 1868.*

, Oscar Harger and C. H. Dwivelle.




« ПредыдущаяПродолжить »